Evaporative cooling apparatus and methods

ABSTRACT

An evaporative cooling apparatus includes a liquid reservoir and a pump coupled to the liquid reservoir. The pump includes a pressure output that applies a static pressure against the liquid stored in the liquid reservoir. The applied pressure forces liquid through a liquid supply line to a nozzle unit, and the liquid is ejected into a stream of forced air from a fan for evaporative cooling applications. The pressure output is also in fluid communication with the nozzle unit via a gas supply line extending between the pressure output and the nozzle unit for delivering gas into the nozzle unit. The gas delivered to the nozzle unit interacts with the liquid inside the nozzle unit to generate the atomized spray of liquid droplets.

BACKGROUND

1. Technical Field

The present invention relates generally to fans and more particularly to devices and methods configured to provide a liquid spray for evaporative cooling applications.

2. Related Art

Rotary fans are generally known in the art and include a motor coupled to one or more fan blades configured to force air through an environment. Conventional fans generally provide little cooling because they merely move air at the ambient temperature. If the air surrounding the fan is warm, then the air stream generated by the fan will also be warm.

Others have attempted to solve the problems associated with conventional cooling fans by providing a liquid spray in the stream of forced air. Evaporative cooling fans, or misting fans, generally utilize the endothermic phase change associated with liquid evaporation to cause a cooling effect in the stream of forced air. For example, U.S. Pat. No. 6,786,701 teaches a high-pressure misting fan configured for injecting a fluid mist into a generated stream of air to produce a cooling vapor impregnated airstream. Similarly, U.S. Pat. No. 6,212,897 teaches a cooling fan with spray function including a fan and a plurality of liquid nozzles attached to the grill of the fan using one or more clamp fasteners.

One problem associated with such conventional misting fans includes excess moisture included in the stream of forced air downstream from the fan. Because conventional fans generally emit relatively large droplets in non-uniform sizes, the air stream may include moisture that is perceptible to a user located downstream of the fan. Such moisture is generally unpleasant and can cause a wet feeling associated with the generated air stream.

Another problem associated with such conventional misting fans includes the location of the water source. Many conventional misting fans require the fan to be coupled to an external water source such as a garden hose. This requirement limits the locations where the fan can be used.

Further problems associated with conventional misting fans are related to the modular arrangement of misting nozzles located on the exterior of the fan grill. The nozzles and/or associated tubing may be inadvertently damaged or disconnected from the liquid source when the fan is being moved, stored, or even during use. External nozzle placement may also decrease the overall aesthetic appeal of the fan assembly.

What is needed, then, are improvements in evaporative cooling devices and methods.

BRIEF SUMMARY

It is an object of the present disclosure to provide an evaporative cooling apparatus that produces a stream of forced air and ejects an atomized spray of liquid droplets into the air stream for evaporative cooling of the air stream.

Another object of the present disclosure is to provide an evaporative cooling apparatus with a pressurized internal liquid reservoir.

A further object of the present disclosure is to provide a misting fan including one or more misting nozzles located on the inner side of the fan grill.

An additional object of the present disclosure is to provide a fan cover having a fan grill including one or more nozzle sockets integrally formed in the fan grill.

In some embodiments, the present disclosure provides an apparatus for dispensing an atomized spray of liquid droplets into a stream of forced air generated by a fan. The apparatus includes a liquid reservoir and a pump having a pressure output configured to emit pressurized gas. A fan cover is attached to the fan, and a nozzle unit is disposed on the fan cover. The nozzle unit is configured to dispense the atomized spray of liquid droplets into the forced air stream generated by the fan. A liquid supply line is disposed between the liquid reservoir and the nozzle unit. The liquid supply line is configured to deliver liquid from the liquid reservoir to the nozzle unit. A gas supply line is also disposed between the pump and the nozzle unit. The gas supply line is configured to deliver gas from the pump to the nozzle unit. The pressure output of the pump is in fluid communication with both the liquid reservoir and the gas supply line.

In further embodiments, the present disclosure provides a method of cooling a stream of forced air from a fan. The method includes the steps of: (a) providing a liquid reservoir coupled to a pressure output from a pump such that the pressure output is in fluid communication with the liquid reservoir, wherein the pressure output on the pump is also coupled to a spray nozzle such that the pressure output is also in fluid communication with the spray nozzle; (b) applying pressure from the pressure output against the liquid stored in the liquid reservoir while simultaneously forcing gas from the pressure output through a gas supply line extending from the pressure output to the spray nozzle; and (c) forcing liquid from the liquid reservoir into a liquid supply line extending from the liquid reservoir to the spray nozzle.

An additional object of the present disclosure is to provide a fan grill having an inner side configured for facing toward the fan and an outer side configured for facing away from the fan. A nozzle socket is integrally formed in the fan grill. The nozzle socket includes a nozzle socket opening shaped to receive a spray nozzle.

Numerous other objects, features and advantages of the present disclosure will be readily apparent to those skilled in the art upon a reading of the following description when taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a perspective view of an embodiment of an evaporative cooling apparatus in accordance with the present disclosure.

FIG. 2 illustrates a front elevation view of an embodiment of an evaporative cooling apparatus in accordance with the present disclosure.

FIG. 3 illustrates a side elevation view of an embodiment of an evaporative cooling apparatus in accordance with the present disclosure.

FIG. 4 illustrates a rear perspective view of an embodiment of an evaporative cooling apparatus in accordance with the present disclosure.

FIG. 5 illustrates a detail perspective view of an embodiment of a base of an evaporative cooling apparatus in accordance with the present disclosure.

FIG. 6 illustrates a detail perspective view of an embodiment of a support tower including a valve control in accordance with the present disclosure.

FIG. 7 illustrates a detail perspective view of an embodiment of a base of an evaporative cooling apparatus including a removable filter cover in accordance with the present disclosure.

FIG. 8 illustrates a rear perspective view of an embodiment of an evaporative cooling apparatus with housing panels removed.

FIG. 9 illustrates a detail rear perspective view of the embodiment of a base of an evaporative cooling apparatus with the base cover and front and back cover portions removed.

FIG. 10. illustrates a detail front perspective view of an embodiment of a fan head of an evaporative cooling apparatus in accordance with the present disclosure.

FIG. 11 illustrates a partial rear perspective view of a fan head showing first, second, and third nozzle units and associated plumbing located on the interior of the fan grill.

FIG. 12 illustrates a detail perspective view of Section 12 from FIG. 11 showing an embodiment of a nozzle unit mounted in a nozzle socket on a fan grill.

FIG. 13 illustrates an exploded detail perspective view of an embodiment of a nozzle unit positioned for insertion into a nozzle socket on a fan grill.

FIG. 14 illustrates a perspective view of an embodiment of a nozzle unit in accordance with the present disclosure.

FIG. 15 illustrates an exploded perspective view of an embodiment of a nozzle unit in accordance with the present disclosure.

FIG. 16 illustrates a cross-sectional view of an embodiment of a nozzle unit in accordance with the present disclosure.

FIG. 17 illustrates a detail perspective view of Section 17 from FIG. 11 showing an embodiment of a fluid coupling and a gas coupling disposed on the interior of a fan grill in accordance with the present disclosure.

FIG. 18 illustrates a schematic of an embodiment of an evaporative cooling apparatus in accordance with the present disclosure.

FIG. 19 illustrates a perspective view of an embodiment of an outer side of a fan cover in accordance with the present disclosure.

FIG. 20 illustrates a perspective view of an embodiment of an inner side of a fan cover in accordance with the present disclosure.

DETAILED DESCRIPTION

Referring now to the drawings, FIG. 1 illustrates an exemplary embodiment of an evaporative cooling apparatus 10. Evaporative cooling apparatus 10 may also be described as a misting fan apparatus 10. In some embodiments, misting fan apparatus 10 includes a fan head 14 generally including a blower for generating a stream of forced air. The blower can include a conventional bladed fan including a motor 40 and plurality of fan blades operatively coupled to the motor via a rotating shaft. Motor 40 may be housed in a motor grill 24, seen in FIG. 3. to allow air flow around the motor for cooling the motor. In other embodiments, evaporative cooling apparatus 10 may include other suitable types of blowers known in the art. The fan blades 42 a, 42 b, 42 c are located in a fan cover 22 such that the blades are not openly exposed. Fan cover 22 includes a fan grill 68 having a plurality of ribs in spaced relation to each other. The ribs in fan grill 68 may include an ornamental design such as a spiral shape. The various ribs formed in fan grill 68 may extend radially and/or circumferentially. In some embodiments, fan cover 22 includes a substantially continuous outer perimeter such that air may be forced directionally through fan grill 68 and away from fan head 14. Fan head may include an oscillator for changing the direction of the forced air stream generated by the fan.

Fan cover 22 generally includes an outer side 69, seen in FIG. 19, configured to face substantially away from the fan when installed on a fan. Fan cover 22 also includes an inner side 71, seen in FIG. 20, configured to face substantially toward the fan when installed on a fan. The inner side 71 of fan cover 22 may form an interior void for accommodating fan blades in some embodiments.

Evaporative cooling apparatus 10 also includes a support tower 16 including a support pole 48, seen in FIG. 8. Support tower 16 may also include a front tower housing 18 a and a rear tower housing 18 b. The front and rear tower housings 18 a, 18 b enclose support pole 48, along with additional components on evaporative cooling apparatus 10.

A base 12 is located at the bottom of support tower 16. Base 12 is generally configured to rest against a surface upon which evaporative cooling apparatus 10 is positioned. Base 10 generally includes a liquid reservoir 50, seen in FIG. 8. Liquid reservoir 50 may include a refillable tank in some embodiments. A removable tank cap 58 may be disposed on liquid reservoir 50 for refilling and sealing the tank. Liquid reservoir 50 is housed inside a base housing 20, seen in FIG. 1. Base housing 20 may include a molded plastic cover enclosing liquid reservoir 50 and additional components on evaporative cooling apparatus 10.

Referring to FIG. 2, evaporative cooling apparatus 10 includes a plurality of misting nozzle units 64 a, 64 b, 64 c. A nozzle unit 64 may be described as a misting nozzle or a spray nozzle. Each nozzle unit 64 is in fluid communication with liquid reservoir 50 via tubing, or plumbing, extending between the reservoir and the nozzle unit. In some embodiments, the tubing is at least partially housed within front and/or rear tower housings 18 a, 18 b. During use, each nozzle unit is configured to eject a spray of atomized liquid droplets. The droplets are ejected into a stream of forced air generated by the fan, and the droplets may evaporate in the forced air stream. The endothermic phase change associated with evaporation of the atomized liquid droplets results in a cooling effect on the forced air stream generated by the fan. As a result, the temperature of the air may be locally cooled downstream from the fan.

Referring to FIG. 10, in some embodiments, fan grill 68 on fan head 14 includes a plurality of nozzle sockets 66 a, 66 b, 66 c. Each nozzle unit 64 a, 64 b, 64 c may be mounted in a corresponding nozzle socket 66 a, 66 b, 66 c. In some embodiments, each nozzle socket includes a cavity accessible from the interior side of fan grill 68. For example, as seen in FIG. 13, in some embodiments, nozzle socket 66 is integrally formed on fan grill 68. Nozzle socket 66 may be integrally formed in the fan grill 68 on fan cover 22 as a unitary construction, such as but not limited to in an injection molding or other suitable manufacturing process. In other embodiments, nozzle socket 66 may include a separate component attached to fan grill 68.

Nozzle socket 66 includes a socket opening 76 shaped for axially receiving nozzle unit 64. As such, fan grill 68 may be molded or otherwise formed to include a nozzle socket 66. This configuration may facilitate more efficient assembly of evaporative cooling apparatus 10 as nozzle unit 64 merely has to be inserted into nozzle socket 66.

In some embodiments, nozzle socket 66 includes a socket flange 78 extending radially inwardly from nozzle socket 66 on the side of nozzle socket 66 opposite socket opening 76. Socket flange 78 may be positioned nearer outer side 69 of fan cover 22 than inner side 71 of fan cover 22. Socket flange 78 provides an axial stop for nozzle unit 64 to keep nozzle unit 64 from being pushed too far through nozzle socket 66 during installation or use. Socket flange 78 may also be integrally formed on nozzle socket 66 in some embodiments.

Referring further to FIG. 13, in some embodiments, nozzle unit 64 includes one or more guides 82 a, 82 b extending from nozzle unit 64. For example, a first guide 82 a extends upwardly from nozzle unit 64, and a second guide 82 b extends downwardly from nozzle unit 64. Each guide 82 a, 82 b is positioned to engage a corresponding guide recess 84 a, 84 b defined on nozzle socket 66. First guide 82 a may be received in first guide recess 84 a, and second guide 82 b may be received in second guide recess 84 b when nozzle unit 64 is installed in nozzle socket 66.

It is generally desirable to retain nozzle unit 64 in nozzle socket 66 after nozzle unit 64 has been inserted into nozzle socket 66. In some embodiments, one or more securement recesses 86 a, 86 b may be defined on guides 82 a, 82 b. Each securement recess 86 a, 86 b may be engaged by a resilient clip member extending into a guide recess 84 a, 84 b to secure nozzle unit 64 in nozzle socket 66.

An atomized spray of droplets may be selectively emitted from nozzle unit 64 during operation of evaporative cooling apparatus 10. Nozzle unit 64 is configured to provide an atomized spray of liquid droplets having substantially uniform size characteristics in a desirable size range for optimal evaporation. To achieve a desired atomized spray of liquid droplets, nozzle unit 64 includes a gas input and a liquid input. The gas input may also be described as a gas port, and the liquid input may also be described as a liquid port. During use, gas flows through nozzle unit 64 and interacts with a liquid also travelling through nozzle unit 64. Following the interaction of the liquid and gas inside nozzle unit 64, an atomized spray of liquid droplets may be ejected from nozzle unit 64. In other embodiments, the atomized spray of liquid droplets is formed after one or more liquid jets are emitted from nozzle unit 64.

Referring to FIG. 12, in some embodiments, each nozzle unit 64 is coupled to both a gas feed tube 102 and a liquid feed tube 104. The gas feed tube 102 and liquid feed tube 104 may be collectively described as nozzle tubing. Gas feed tube 102 is in fluid communication with a gas supply line 44, and liquid feed tube 104 is in fluid communication with a liquid supply line 46. Gas supply line 44 is defined as one or more tubes extending between the pump and the nozzle unit 64 for delivering gas from the pump to the nozzle unit. Liquid supply line 46 is defined as one or more tubes extending between the liquid reservoir and the nozzle unit for delivering liquid from the liquid reservoir to the nozzle unit. Gas feed tube 102 may be described as a portion of gas supply line 44, and liquid feed tube 104 may be described as a portion of liquid supply line 46. During use, a gas travels through gas feed tube 102 into nozzle unit 64, and a liquid travels through liquid feed tube 104 into nozzle unit 64. In some embodiments, one or more feed tube clips 106 may extend from the inner side of fan grill 68 toward the interior of fan grill 68 for securing gas feed tube 102 and/or liquid feed tube 104. In some embodiments, each feed tube clip 106 is integrally formed on fan grill 68.

Referring to FIG. 14, in some embodiments, gas feed tube 102 attaches to nozzle unit 64 via a gas feed tube connector 94, such as a barbed hose fitting. Similarly, liquid feed tube 104 attaches to nozzle unit 64 via a liquid feed tube connector 92, such as a barbed hose fitting in some embodiments.

Referring to FIGS. 15 and 16, nozzle 64 includes internal features for providing a desired interaction between the incoming gas and liquid streams for providing an atomized spray of liquid droplets. In some embodiments, a liquid channel 114 is defined in nozzle 64. Liquid channel 114 extends axially from liquid connector 92 into nozzle body 90. Nozzle body 90 forms an annular shell having a hollow interior. Liquid conduit 144 which defines liquid channel 114 extends partially into the hollow interior of nozzle body 90, forming an annular void 124 between nozzle body 90 and the liquid conduit 144. Liquid conduit 144 may be described as a liquid capillary tube in some embodiments. Liquid conduit 144 generally forms a tube-shaped member extending from nozzle body 90 toward pressure cap 88. Liquid channel 114 terminates at a liquid channel opening 116 inside the hollow interior of nozzle body 90. During use, liquid travels through liquid channel 114 in liquid conduit 144 toward liquid channel opening 116. Liquid conduit 144 includes a tapered end at the end closest to liquid channel opening 116, as seen in FIG. 15 and FIG. 16, in some embodiments. In some embodiments, nozzle unit 64 is configured to operate using a flow-blurring nozzle geometry. In such embodiments, an axial gap exists between liquid channel opening 116 and the axial position of pressure cap end wall 98 and/or the beginning of pressure chamber exit orifice 88. The axial gap distance between the axial end of liquid conduit 144 adjacent liquid channel opening 116 and the pressure chamber exit orifice 88 defines a distance H. In some embodiments, the ratio of H divided by the diameter of the pressure chamber exit orifice is less than about 0.25. In such embodiments, a reflux cell of liquid and gas may be formed inside liquid channel 114 on liquid conduit 144 upstream of liquid channel opening 116. The reflux cell may be formed when gas travels from pressure chamber 110 axially upstream into liquid channel 114 and forms a region of toroidal vorticity with liquid travelling through liquid channel 114. Such a geometric configuration for nozzle unit 64 may produce a spray of atomized liquid droplets having desired characteristics for improved evaporative cooling effect.

A pressure cap 80 is attached to nozzle body 90 in some embodiments. Pressure cap 80 generally includes an annular sleeve having a pressure cap end wall 98 extending radially inwardly from one end of the sleeve. Pressure cap 80 includes an open end shaped for axially receiving nozzle body 90. Pressure cap 80 provides a pressure chamber 110 inside nozzle unit 64. Pressure chamber 110 generally includes an interior chamber that is filled with gas via gas port 112. During use, gas enters gas port 112 via gas feed tube 102. The gas fills the annular void 124 and travels toward a pressure chamber exit orifice 88 defined in the pressure cap end wall 98. As the gas travels past liquid channel opening 116, the gas interacts with liquid exiting liquid channel 114. The gas may flow temporarily upstream a short distance into liquid channel 114 in some embodiments before exiting pressure chamber exit orifice 88. The interaction of the liquid and gas near the liquid channel opening 116 and the pressure chamber end wall 98 forms an atomized spray of liquid droplets that is ejected from the nozzle unit 64.

It is noted that liquid channel 114 does not extend to the axial location of pressure chamber end wall 98 but rather stops such that a gap exists between liquid channel opening 116 and pressure chamber end wall 98. The gap also exists between liquid channel opening 116 and pressure chamber exit orifice 88. The gap provides a location for the gas travelling through pressure chamber 110 to intercept liquid travelling from liquid channel opening 116 toward pressure chamber exit orifice 88.

As seen in FIG. 15 and FIG. 16, in some embodiments, an annular pressure cap seal 108 may be disposed between pressure cap 80 and nozzle body 90 to prevent gas from leaking from pressure chamber 110.

Pressure cap 80 may be attached to nozzle body 90 using any suitable attachment means, including but not limited to a mechanical engagement or an adhesive. In other embodiments, pressure cap 80 and nozzle body 90 may be integrally formed in a unitary construction. In an exemplary embodiment, nozzle body 90 includes a nozzle body thread 120, and pressure cap 80 includes a corresponding pressure cap thread 122 such that pressure cap 80 may be screwed onto nozzle body 90.

Liquid and gas must travel into nozzle unit 64 in a controlled manner to produce an atomized spray of liquid droplets. The liquid and gas flow on evaporative cooling apparatus 10 is provided by a pump 60, seen in FIG. 8 and FIG. 9. Pump 60 generally includes an air pump, or compressor. Pump 60 may include a centrifugal pump, or a centrifugal compressor, in some embodiments. Pump 60 could also include other suitable types of pumps or compressors, including radial or axial compressors, for providing a pressurized gas output. Pressurized gas is provided to gas supply line 44 via a pressure output 72 extending from pump 60 to gas supply line 44. Pressure output 72 is coupled to the gas supply line 44 and is in fluid communication with the gas supply line.

Pump 60 also provides a static pressure inside liquid reservoir 50 in some embodiments. In other embodiments, static pressure inside liquid reservoir 50 may be provided by a secondary pressure source. As seen in FIG. 9, a pressure coupling 74 generally includes a union-tee coupling in some embodiments. Pressure output 72 provides an input to pressure coupling 74, and gas supply line 44 extends from pressure coupling 74 in some embodiments. A second output from pressure coupling 74 includes a tube extending to liquid reservoir 50. As such, pressurized gas provided by pump 60 via pressure output 72 applies a static pressure in liquid reservoir 50 and also travels through pressure coupling 74, into gas supply line 44, into gas feed tube 102, through gas port 112, into pressure chamber 110 and out pressure chamber exit orifice 88. Pressure is established in the gas supply line 44, causing a static pressure to be applied to the interior of liquid reservoir 50 due to the fluid communication between fluid coupling 74 and liquid reservoir 50.

In various embodiments, pump 60 may form a pressure source for providing static pressure inside liquid reservoir and for simultaneously providing a flow of gas to the nozzle unit. In such embodiments, pump 60 may be interchangeable with any suitable pressure source such as a vessel or a supply of a compressed gas.

The pressure applied to liquid stored in liquid reservoir 50 can be used to deliver the liquid to liquid supply line 46. For example, as seen in FIG. 18, pump 60 intakes air and applies pressure to both liquid reservoir 50 and gas supply line 44 via pressure output 72. Because liquid reservoir 50 is closed, the pressure applied to liquid stored in liquid reservoir 50 may cause the liquid to advance upwardly through liquid supply line 46 to nozzle unit 64 at the same time gas flow is supplied through gas supply line 44 to nozzle unit 64. The nozzle unit 64 may be generally located downstream of a fan 200 forcing a stream of air 202 over the nozzle unit 64.

In some embodiments, the pressure generated by pump 60 is between about 10 psi and about 50 psi. In further embodiments, pump 60 provides a pressure of between about 20 psi and about 30 psi. It is noted that the numeric pressure values recited here are only for exemplary purposes associated with certain embodiments, and it is contemplated within the scope of the invention that other pressure ranges not disclosed herein may be suitable in other embodiments. In some embodiments, a pressure relief valve 128, seen in FIG. 18, is in fluid communication with liquid reservoir 50. Pressure relief valve 128 may prevent liquid reservoir 50 from exploding in the event that pressure begins to build up in liquid reservoir 50.

Because of the small dimensions of the liquid channel 114 and the pressure chamber exit orifice 88, it is possible that debris could clog nozzle unit 64. Such clogging could prevent proper operation of evaporative cooling apparatus 10 and could further cause gas and/or liquid pressure buildup that could damage evaporative cooling apparatus 10. One or more line filters 52, 54 may be attached to gas supply line 44 and/or liquid supply line 46 to prevent debris from entering nozzle unit 64. For example, a gas line filter 52 is disposed along gas supply line 44 between base 12 and head 14. Similarly, a liquid line filter 54 is disposed along liquid supply line 46 between base 12 and head 14. Each filter may need to be replaced periodically depending on the frequency of use of evaporative cooling apparatus 10 and the cleanliness of air and water used in evaporative cooling apparatus 10.

A removable filter cover 26 is detachably secured to support tower 16. Filter cover 26 may be manually removed by a user to access filters 52, 54, as seen in FIG. 7. In some embodiments, filter cover 26 is disposed on the rear side of support tower 16.

Referring again to FIG. 10, in some embodiments fan head 14 includes three nozzle units 64 a, 64 b, 64 c. Each nozzle unit is supplied gas and liquid from gas supply line 44 and liquid supply line 46, respectively. To ensure liquid and gas are available to each nozzle unit, nozzle tubing may be disposed on the inner side of fan grill 68 between the fan and the fan grill 68. The nozzle tubing generally extends radially outwardly from a central union on each line to each individual nozzle unit. For example, as seen in FIG. 11 and FIG. 17, in some embodiments, a liquid union 130 includes a liquid union fitting 134 configured to be connected to liquid supply line 46. Liquid union 130 includes a three-way union in some embodiments. A first liquid feed tube 140 a extends from liquid union 130 toward first nozzle unit 64 a. A second liquid feed tube 140 b extends from liquid union 130 toward second nozzle unit 64 b, and a third liquid feed tube 140 c extends from liquid union 130 toward third nozzle unit 64 c. Additionally a gas union 132 includes a gas union fitting 136 configured to be connected to gas supply line 44. Gas union 132 includes a three-way union in some embodiments. A first gas feed tube 142 a extends from gas union 132 toward first nozzle unit 64 a. A second gas feed tube 142 b extends from gas union toward second nozzle unit 64 b. A third gas feed tube 142 c extends from gas union 132 toward third nozzle unit 64 c.

Referring further to FIG. 17, in some embodiments, one or more head check valves 138 a, 138 b, 138 c may be disposed on the tubing extending from liquid union 130. For example, a first head check valve 138 a is attached to first liquid feed tube 142 a, a second head check valve 138 b is attached to second liquid feed tube 142 b, and a third head check valve 138 c is attached third liquid feed tube 142 c. Each head check valve provides a resistance to liquid flowing toward the nozzle units. When the apparatus is turned off, static pressure may remain applied against the liquid in the reservoir by the pressure output of the pump. That pressure may cause liquid to temporarily continue to flow into each nozzle unit after the gas flow is terminated. Such momentary flow of the liquid to the nozzle units could cause non-atomized liquid droplets to settle in the nozzle unit or be ejected from the nozzle unit. However, check valves 138 a, 138 b, 138 c provides resistance to the liquid flowing from liquid union 130 to prevent further introduction of liquid into the nozzle units after the device is turned off while the residual gas pressure bleeds out of the system.

Referring to FIGS. 6-8, in some embodiments, the flowrate of liquid through liquid supply line 46 can be controlled by a liquid valve 56. Liquid valve 56 may include any suitable type of valve for regulating the flowrate of a liquid. Liquid valve 56 includes a valve control 34 extending therefrom and accessible from the outside of housing 18. Liquid valve 56 is disposed on the interior of housing 18, and particularly on the inside of rear housing 18 b on the rear side of support tower 16 in some embodiments. Valve control 34 is thus not visible from the front of evaporative cooling apparatus 10 in some embodiments. By adjusting the valve control 34, a user may adjust the liquid flowrate to the nozzle unit and thus the level of misting provided by the apparatus.

In some embodiments a total gas flowrate of between about 9 and about 12 liters per minute provides an atomized spray of liquid droplets from the nozzle units 64 a, 64 b, 64 c. Because the total gas flow rate is distributed among three nozzle units in some embodiments, a gas flow rate of about three to four liters per minute from each nozzle unit is provided. The gas union 132 distributes the gas flowrate proportionately to the individual nozzle units 64 a, 64 b, 64 c for ejection from the apparatus. The total gas flowrate may be constant during use and may be controlled by the pressure generated by pump 60 in some embodiments. Additionally, the liquid flowrate required to achieve a desired spray is variable and may be controlled by a user using valve control 34. The valve 56 can be closed, resulting in a liquid flowrate of zero. Valve 56 when fully opened may provide too much liquid to each nozzle unit in some applications. To limit the maximum liquid flowrate achievable through valve 56 when valve control 34 is at its maximum setting, a flow restrictor may be integrated into liquid line filter 54. The flow restrictor includes a region in the liquid supply line 46 having a smaller inner diameter than the diameter in the main line. In some embodiments, the flow restrictor includes an inner diameter of between about 0.1 and about 0.3 mm. In additional embodiments, the flow restrictor includes an inner diameter of about 0.18 mm. In some embodiments, the liquid flowrate to each nozzle may range between about zero mL/min to about 100 mL/min. In additional embodiments, a liquid flowrate to each nozzle may be between about zero mL/min and about 10 mL/min. In further embodiments, the a preferred maximum liquid flowrate to each nozzle is about 10 mL/min. In other embodiments, depending on the dimensions of the apparatus, the gas flowrate, liquid flowrate, flow restrictor inner diameter, and applied pressure required to produce a desired atomized spray may increase or decrease and is not limited to the embodiments described above.

The evaporative cooling apparatus 10 described herein may be operated in numerous modes. A control panel 32 is disposed on base 12 in some embodiments. Control panel 32 may include one or more controls for operating evaporative cooling apparatus 10. In a first mode, or a non-misting mode, the apparatus may be operated with only the fan turned on and liquid flowing to the fan head. In a second mode, or a misting mode, the apparatus may be operated with both the fan turned on and liquid flowing to the fan head.

Thus, although there have been described particular embodiments of the present invention of a new and useful Evaporative Cooling Apparatus and Methods, it is not intended that such references be construed as limitations upon the scope of this invention except as set forth in the following claims. 

What is claimed is:
 1. An apparatus for dispensing an atomized spray of liquid droplets into a stream of forced air generated by a fan, the apparatus comprising: a liquid reservoir; a pump having a pressure output configured to emit pressurized gas; a fan cover attached to the fan; a nozzle unit disposed on the fan cover, the nozzle unit configured to dispense the atomized spray of liquid droplets into the forced air stream generated by the fan; a liquid supply line disposed between the liquid reservoir and the nozzle unit, the liquid supply line configured to deliver liquid from the liquid reservoir to the nozzle unit; and a gas supply line disposed between the pump and the nozzle unit, the gas supply line configured to deliver gas from the pump to the nozzle unit, wherein the pressure output of the pump is in fluid communication with both the liquid reservoir and the gas supply line.
 2. The apparatus of claim 1, further comprising: a nozzle socket integrally formed in the fan grill, wherein the nozzle unit is mounted in the nozzle socket.
 3. The apparatus of claim 1, further comprising: the fan cover including an inner side substantially facing the fan and an outer side substantially facing away from the fan, wherein the nozzle unit is mounted in the nozzle socket from the inner side of the fan cover.
 4. The apparatus of claim 1, further comprising: a support tower including a tower housing, wherein the liquid supply line and the gas supply line are enclosed in the tower housing.
 5. The apparatus of claim 1, wherein: the pressure output is configured to simultaneously apply a static pressure to the liquid reservoir and to force gas through the gas supply line toward the nozzle unit.
 6. The apparatus of claim 5, wherein the static pressure is between about 10 psi and about 50 psi.
 7. The apparatus of claim 5, wherein the static pressure is between about 20 psi and about 30 psi.
 8. The apparatus of claim 5, further comprising: a relief valve attached to the liquid reservoir.
 9. The apparatus of claim 1, the nozzle unit further comprising: a nozzle body forming a hollow interior and a liquid conduit extending axially into the hollow interior, the liquid conduit defining an axial liquid channel; and a pressure cap disposed on the nozzle body, the pressure cap defining a pressure chamber inside the hollow interior of the nozzle body.
 10. The apparatus of claim 9, wherein: the liquid supply line is in fluid communication with the liquid channel in the liquid conduit; and the gas supply line is in fluid communication with the pressure chamber.
 11. The apparatus of claim 1, further comprising: a second nozzle unit disposed on the fan grill; and a third nozzle unit disposed on the fan grill, wherein the second and third nozzle units are both in fluid communication with the liquid supply and with the gas supply line.
 12. A method of cooling a stream of forced air from a fan, comprising: (a) providing a liquid reservoir coupled to a pressure output from a pump such that the pressure output is in fluid communication with the liquid reservoir, wherein the pressure output on the pump is also coupled to a spray nozzle such that the pressure output is simultaneously in fluid communication with the spray nozzle; (b) applying pressure from the pressure output against the liquid stored in the liquid reservoir while simultaneously forcing gas from the pressure output through a gas supply line extending from the reservoir to the spray nozzle; and (c) forcing liquid from the liquid reservoir into a liquid supply line extending from the liquid reservoir to the spray nozzle.
 13. The method of claim 12, further comprising: forcing gas from the gas supply line into the spray nozzle; and forcing liquid from the liquid supply line into the spray nozzle.
 14. The method of claim 13, further comprising: interacting the gas and liquid in the spray nozzle; and ejecting an atomized spray of liquid droplets from the spray nozzle.
 15. The method of claim 13, wherein: the atomized spray of liquid droplets is ejected into a stream of forced air from the fan.
 16. The method of claim 15, further comprising: reducing the temperature of the stream of forced air.
 17. The apparatus of claim 12, wherein: the liquid is forced into the liquid supply line solely by the pressure applied from the pressure output on the liquid stored in the liquid reservoir.
 18. An apparatus for covering a fan, comprising: a fan grill having an inner side configured for facing toward the fan and an outer side configured for facing away from the fan; and a nozzle socket integrally formed in the fan grill, the nozzle socket including a nozzle socket opening shaped to receive a spray nozzle.
 19. The apparatus of claim 18, further comprising: a spray nozzle inserted into the nozzle socket, the spray nozzle including a liquid channel and a gas port.
 20. The apparatus of claim 19, further comprising: a socket flange extending from the nozzle socket into the nozzle socket opening, wherein the socket flange is positioned nearer the outer side of the fan grill than the inner side of the fan grill, wherein the socket flange provides an axial stop for the spray nozzle. 